DISCLAIMER: What follows is a description of a play that took place in the third quarter of a preseason game, against a second-string offensive tackle who at this time last year was preparing for his senior season at Temple.

Still, the sequence of events was a sight to behold.

First, Derek Barnett beat Dion Dawkins on a speed rush off the left edge, forcing Bills quarterback Nathan Peterman to scramble to his right. Then, with Dawkins chasing him like a dropped dollar bill on a windy day, Barnett reversed course, barging through some traffic on the opposite side of the pocket to force his target to tuck the ball and run. Then, as Peterman made a diagonal beeline for the sideline, Barnett chased him down, landing on top of the quarterback as he tumbled to the ground 10 yards down field.

On a hurricane map, the charted course would have looked something like an elongated bass clef, or a partially completed "6." On the stat sheet, it didn't even count as a tackle (cornerback Aaron Grymes got there first). Still, it was one of those show-me-something moments, a tiny morsel of relevance in a game mostly devoid of meaning.

"I've been saying since Day 1: You ask me about Derek Barnett, he has a motor," linebacker Jordan Hicks said after the Eagles' 20-16 preseason victory over the Bills. "He does not quit on any play. He's going to continue to come after you, down after down after down."

After three weeks of practices and two preseason games, Barnett has done little to suggest that he doesn't deserve a significant role in the Eagles' rotation at defensive end this season. Against the Bills, he recorded his third sack in two preseason games, and it's a compliment to say that the statistic is almost an afterthought. That's how impressive the rookie has been on a down-to-down basis.

Poll

Does LeGarrette Blount have enough left in the tank to help the Eagles?

Yes

No

The question of whether he supplants current starter Vinny Curry is less a matter of whether as it is when. While it is true that Jim Schwartz likes to rotate his defensive ends, it's also true that he called on his top two edge rushers almost twice as often as Edge No. 3 in his rookie season as Eagles defensive coordinator.

In 2016, Edge No. 3 was Curry, who entered Thursday night's game against the Bills as the starter opposite Brandon Graham. Preseason depth charts mean very little. Heck, same goes for regular-season depth charts, the Eagles version of which had Mychal Kendricks listed as a starter throughout a 2016 season in which he barely played a quarter of the snaps. Still, it'll be interesting to see what how much Schwartz mixes in Barnett against the first-teamers in next week's dress-rehearsal game against the Dolphins.

"Man, I'm excited to see him to continue to grow and mature and get with B.G. and Chris Long and these guys who have played this game for a long time and learn," Hicks said. "He's going to be a special player."

One thing that is beyond dispute: The Eagles need more production from their front four if they hope to make any significant gains on last year's lackluster campaign. It's not that the pass rush was bad in 2016. It just wasn't good enough to stop opposing defenses from marching up and down the field at will over the back half of the schedule. Some of the blame goes to the pitiful play at cornerback that the Eagles got; quarterbacks like Kirk Cousins and Andy Dalton were taking three steps and firing at will. At the same time, Troy Vincent and Bobby Taylor aren't walking through that door. Ronald Darby looks like he could be half of a passable rendering, but that still leaves the problem 50 percent unsolved.

(A note on Darby: His speed and acceleration have been on display throughout his first week as an Eagle, including last night, when he picked off a Tyrod Taylor jump ball in the middle of the field and returned it 48 yards deep into Buffalo territory late in the first quarter. He's remarkably quick to the ball, he's solidly built, and he seems to possess the aggressive mentality that Schwartz likes in his corners . . . he nearly had another interception earlier in the first quarter when he jumped an Anquan Boldin out pattern but bobbled and dropped the ball.)

Back to the pass rush. . .

It didn't live up to expectations last year, but that might've had more to do with the quality of the expectations than the quality of the living, given the lack of speed on the edge that the Eagles possessed. Even now, it isn't clear exactly how much pure pass-rushing talent the Eagles have. There's a lot of hype, and a lot of projection, but it takes a lot more than press clippings and film grades to knock a quarterback to the ground. The reality is that the four projected starters on the defensive line have combined for 89.5 sacks in 286 career games. None has reached 10 sacks in a season, and in their 20 combined seasons they've reached seven sacks twice.

Maybe what the Eagles got is what they should have expected. They tallied 34 sacks in 587 drop backs for a 5.8 percent rate that ranked 14th out of 32 teams. Like last year, there are a lot of ifs.

If Timmy Jernigan can emerge as a consistent 4-3 pass-rushing threat next to Fletcher Cox . . .

If Cox can put together 16 games' worth of his most dominant stretches . . .

If Curry can finally become the player a lot of people swear he is (including the front office that signed him to a contract extension that this year will make him one of the highest-paid defensive ends in the game) . . .

That last one, well, let's just say the evidence continues to mount against it.

In Barnett, the Eagles have their biggest unknown. And, perhaps, their best reason to hope.